Reusing the same key is fatal to the one-time pad--it does not matter which characters were used in the creation of the truly-random key, from all the possible values on the keyboard, just numbers, just letters, binary, whatever. It can only be used once: that is why they call it the one-time pad.
By definition the one-time pad was generated in a truly random manner. Given such a key that has been properly safeguarded, there is no known attack against it if the one-time pad is properly applied--the key must be at least as long as the plaintext. It is often called the perfect cipher.